N, n&#39;-disubstituted piperazines and process of preparing same



Patented Apr. 21, 1953 UNITED STATES PATENT OFFICE N,N-DISUBSTITUTED PIPERAZINES AND PROCESS OF PREPARING SAME Arthur W. Weston, Waukegan, and Kenneth E. Hamlin, Jr., Gumee, Ill., assignors to Abbott of Illinois Laboratories, North Chicago, 111., a corporation N Drawing. Application April 12, 1949,

Serial No. 87,116

Claims. (01. 260---268) Our invention relates to new chemical compounds and more particularly to certain heterocyclic compounds, containing as the essential constituenta N,N-disubstituted piperazine ring and salts thereof.

The novel compounds of our invention are variously useful. It has been observed that the compounds claimed herein according to the invention show antihistaminic and antispasmodic activity.

The present invention comprises novel compounds containing the piperazine ring and having the following formula:

N-Rc-morpholine of the with the Ri-amine under pressure;

(4) Treatment of an N-Rz-fi,fi'-dihalodiethylamine or an N- RzCI-lz)- 3,;9'-dihydroxydiethylamine with the formula:

CH2 OHQ'Z GHz-CHz-Z' with an Ri-amine. In the above formula Z and Z are either halogen or hydroxy groups;

(5) Treatment of an N-Rz-fi,B-diaminodiethylamine of the formula:

under such conditions of heating as will cause ammonia to split out of the molecule. The group R1- may be introduced by treating the resulting Rz-piperazine compound with an RiX;

(6) Treatment of an N-Rz-fl-hydroxy-E- aminodiethylamine of the formula:

CHz-CHz-OH under such conditions of heating as will cause a molecule of water to split out of the intermediate. The R1- group may be introduced by treating the resulting Rz-piperazine with an RlX.

(7) Treatment of an N-R2-B,/8'-di-R1-diaminodiethylamine of the formula:

CHPCH? under such conditions of heating as will cause Ri-amine to split out and form the corresponding N-R1-N-Rz-piperazine;

(8) Treatment of an Rz-amine with an N-R1/ 13-dihalodiethylamine as indicated by the following reaction:

to split out two moles of hydrohalic acid and produce the corresponding N-R1-N'-R2-piperazine;

(9) The finalcompounds of the invention may also be prepared where R1 is methyl or ethyl from an N-Rz-piperazine, by reacting this compound with either formaldehyde or acetaldehyde in conjunction with formic acid in which case the substituted RI is methyl or ethyl, respectively. The polymer of formaldehyde, paraformaldehyde or formalin, may be used in place of formaldehyde;

(10) Treatment of an N-monoacyl derivative of piperazine in which the acyl group contains up to four carbon atoms inclusive, with an R2- halide followed by reduction of the acyl group to the corresponding alkyl group With a reducing agent such as formic acid or lithium aluminum hydride.

The Rz-piperazines which are both valuable therapeutics and also valuable intermediates for the preparation of those final compounds of the invention wherein RI is other than a hydrogen v atom, may be prepared by reacting an 1 T-car-' bethoxypiperazine with a compound of the formula Rz-X to produce the corresponding N-Rz-N'-carbethoxypiperazine. This product is then hydrolyzed and decarboxylated to produce the desired N-Rz-piperazine, p

In our process (3) above the N-Rz-morpholine may be produced by two processes: (a)v reaction of an Rz-halide with morpholine; (b) the treatment of an Rz-amine with a p,c-dihalodiethyl-' ether. 1

In process (4.) above, the compound N,N- (5,153- dihalodiethyl) -NRzamine has been prepared-by reacting diethanolamine with an Rz-halide to produce the N-Rz-diethanolamine. This compound is then treated with hydrohalic acid to produce the desired dihalide. One may also use the N-Rz-diethanolamine directly with the R1- amine to obtain results which are moderately satisfactory.

In the above formulae R1, R2 and X have the same definitions as given previously. In methods (l) and (2) the presence of an alkaline material to neutralize the acid formed from the reaction may be advantageous. The presence of a trace of an alkali-metal iodide such as sodium iodide, in these two methods negates the necessity of a longer refluxing period. It has also By employing about 10.8 g. of pfi-diphenylethyl chloride, 5.0 g. N-methylpiperazine and 5.3 g. of anhydrous sodium carbonate in 100 cc. of dry xylene and refluxing the mixture for 60 hours, there is obtained the product represented by the above structural formula. By adding two equivalentsof hydrogen chloride gas to an absolute a1- CHi-CH:

N-CH:

CHz-C a CHCHT' cohol solution of this base, the dihydrochloride salt of the above base is formed. This compound melts at 278 -279 C. after crystallization from alcohol.

I 7 EXAMPLE II N-(a-naphthylmethyZ) -piperaz2'ne GET-CH2 cHl- N-'H A solution of 8.6 g. of anhydrous piperazine and 17.7 g. of a-chloromethylnaphthalene in 150 cc. of anhydrous ethanol is allowed to stand 17 hours. On filtration N,N-di(a-naphthylmethyl) -piper azine, M. P. 163-164 C. (from ethanol), is recovered.

After concentrating the filtrate in vacuo and making the residue alkaline with a sodium hy- .droxide solution, the mixture is extracted with ether. After drying, the mixture is distilled, N-(a-naphthylmethyl) -piperazine, B. P. 154-156 C. atv 1 mm. is obtained. The monohydrochloride of this base melts at 227 28 C.

EXAMPLE III N- (pmaphthylmethyl) -piperazine CH2CH2 CHzN \NH O Hz-C2 In a manner similar to that of Example II, 8.6'

To a cooled solution of 16 cc. of formic acidand 3.2 cc. of formalin (formaldehyde) is added 5 g. of N-(a-naphthylmethyl)-piperazine. The" mixture is heated on a steam bath for 8 hours. Concentrated hydrochloric acid is then added to make the mixture acidic and the resulting solution is evaporated to dryness in vacuo. The dihydrochloride of N (a naphthylmethyl) N methylpiperazine isolated from this residue has a melting point of 241" C. (with decomposition) from ethanol.

7 EXAMPLE V N fi-naphthylmethyl) -N'-m ethylpiperazine GET-CH2 -oH2 N-CH:

l CH2-C 2 In a manner similar to that of Example IV,

4 g. of N-(fi-naphthylmethyl)-piperazine. 12.51 cc. of formic acid and 2.5 cc. of formalin are re-.

acted to yield the dihydrochloride of N-(B-naphthylmethyl)-N-methylpiperazine, M. P. 281? C.

(with decomposition) when crystallized from ethanol. I

EXAMPLE VI N (a-naphthylmethyl) -N' (p-hydroxyethyl) piperazine CH2-CH1 C Ha-N NC2Hr-O H CHz-C 2 'In 'a mannersimilar to that of Example I, 6.5 g'. of-N-(pmydroxyethyl)-piperazine, 14 g. of v.-chloromethylnaphthalene, 5.3 g. of sodium carbonate and 100 cc. of xylene are combined to yield the dihydrochloride of N-(a-naphthylmethyl) -N-(;9-hydroxyethyl) -piperazine, M. 1?. 205 209 0. (with decomposition). i I

A VII era-N jlna fashion similar to that of Example I, 3.25-

g. of N-(p-hydroxyethyl) -piperazine and 4.66 g. of fl-chloromethylnaphthalene are reacted with n-butanol replacing the hydrocarbon solvent. The product is isolated as the dihydrochloride, having a melting point of 241 C. (with decomposition).

EXAMPLE VIII N- (9-fluorenyl) -N'- (phydroxyethyl) -piperazine In a manner similar to that of Example I, 12 g. of 9-bromofluorene and 6.5 g. of N-(p-hydroxyethyl) -piperazine in butanol are heated on a steam bath for two hours to yield the hydrobromide of N (9 fluorenyl) N (p-hydroxyethyl) -piperazine. This compound is converted to the free base, M. 1?. 143-144 C. (from ethyl acetate) and the dihydrochloride, M. P. 243-244 C. (with decomposition).

EXAMPLE IX N- (ll-fluorenyl) wiperazine CHr-CHI GE's- 0 2 TA mixture of 10 g. ofN-(Q-fluorenyl)-N'-carbethoxypiperazine and 100 cc. of concentrated hydrochloric acid. are refluxed for several hours. The solution is then evaporated to dryness in vacuo. After dissolving the residue in cc. of

warm water, 40% potassium hydroxide solution is added to liberate the free base as an oily supernatant layer. This layeris separated, dried carefully over potassium hydroxide pellets, and distilled. The base is treated with alcoholic hydrogen chloride to produce the dihydrochloride of N-(9-fluoreny1)-piperazine having a melting point of 283-285 C. (with decomposition) after crystallization from ethanol.------- 6 EXAMPLE X I N- (Q-fluorenyl) -N'-methylpiperazine In a similar manner to that of Example I, 12 g. of 9-bromofluorene and 5 g. or N-methylpiperazine in cc. butanol are heated 2% hours on a steam bath to yield 7.5 g. of the dihydrobromide of N-(Q-fiuorenyl)-N-methylpiperazine, M. P. 265-268 C. (with decomposition) after crystallization from ethanol.

EXAMPLE XI (Q-phenanthrylmethyl) -N' -methylpipemzine CHc-CH:

C HE N N-C H: l CHz-C In a similar manner to that of Example I, 7.4

g. of 9-chloromethylphenanthrene and 3.2 g. of N-methylpiperazine in 75 cc. of butanol are heated 2 hours'on a steam bath to yield the dihydrochloride of N (Q-phenanthryl) N- methylpiperazine, M. P. 254-255 C. (with decomposition) after crystallization from ethanol.

tural formula melts at 234-235 C. after re-. crystallization from alcohol. I

- EXAMPLE x111 N-(p-chlorobenzhydryl) -N'-methyl 2 methylpiperazine or N (p-chlorobenzhydryl) N- methyZ-3-methylp2lpemzine Following the procedure of Example I, 13.4 g.

of l,2-dimethylpiperazine or 1,3-dimethylpiper azine, 28 gwof p-chlorobenzhydryl chloride, and

12 g. of anhydrous sodium carbonate in cc oi dry xylene are refluxed for 64 hours to pro-, duce the compound represented I by one .of the.

7 structures above. The. product is a very viscous, light amber oil which boils at l52 -l53 C. at 0.3 mm. The base forms a dipicrate in ether which recrystallizes from ethanol as yellow granules, melting point 194-195 C. (dec.)

EXAIVIPLE XIV 1,3,5-trimethyZ-4-(p chlorobenehydryl) piperazine or 1,2,6-trz'methyZ-4-(p chlorobenzhydrg Z) -piperazine CH3 Cl@ 511-011.

oH-N N-CHi Q ome.

- CH2 o1 on-(EH \CHN N-CH: CHz-CH H3 Using 11.7 g. of the compound prepared in Example XXXEV, 21.7 g. of p-chlorobenzhydryl chloride, and 9.7 g. of anhydrous sodium carbonate, and refluxing the mixture for 26 hours in 100 cc. of dry xylene, the compound having one ofthe above formulas is obtained as a very viscous yellow oil which boils at 177-178 C. at

In the manner of Example I, 4.1 g. of 1,2,5- trimethylpiperazine and 7.6 g. of p-chlorobenz hydryl chloride are condensed by refluxing in;

75 cc. of dry xylene in the presence of 3.4 g. of anhydrous sodium carbonate for 48 hours. The product, represented by the formula above, is collected as a very viscous yellow oil which boils at l50-160 C. at 1 mm. The base forms a.

monopicrate in ether which recrystallizes from-- ethanol as yellow needles melting at 181-182" C. (dec.).

EXAMPLE XVI V N-oni GHQ-oh,

methyldecahydroquinoxaline, 13.7" gof pchlorobenzhydryl chloride, and 6.2 g. of anhydrous sodium carbonate are refluxed in "55cc.

of ,dryxylenefor 46 hours to 'produce'the -com-;

pound represented by the formula above. The product .is a very viscous oil which boils at 1. 6?

o. ext-0.6. mm. -lt-"forms' a dipicrate in ether.

whicm'recrystamzes from absolute ethanol as yellow crystals which begin turning dark at 169 C. and melt at 263C. (dec.)

s V EXAMPLE XVII N- (m v-dzphe'nylallyl) -N' -methylpipemzine CH2CH2 In the manner of Example I, 11.4 g. of w -diphenylallyl chloride, 5 g. of N-methylpiperazine and 5.3 g. of anhydrous sodium carbonate are reacted to form a product of the above structure which boils at 170-173 C. at 0.9 mm. The monohydrate of the monohydrochloride salt melts at 86-87" C. after crystallization from alcohol; the non-hydrated monohydrochloride melts at 139- 140 C.

' EXAMPLE XVIII N- (a-prop ul-p-chlorobenzyl) -Nf -met hylpiper- By employing about 10.2 g. of -a-propyl-pchlorobenzyl chloride, 5.0 g. of N-methylpiperazine, 5.3 g. of anhydrous sodium carbonate and by following the procedure of Example I, the

above product is obtained. It boils'at 142-143 C. at 1.7 mm. The monohydrochloride salt melts at 176-177 C. The dihydrochloride salt melts at 256-257 C. (dec.)

EXAMPLE XIX N-(a-pyridyl) -piperazine 7 NH .1 rem-chi A mixture of 31.6 g. (0.2 mole) of 'a-bromopyridine, 34.4 g. (0.2 mole) of anhydrous piperazine and 20 g. of pyridine is heated in a bomb at C. for six hours. The reaction mixture is then heated on the steam bath with 10 g. of solid sodium hydroxide for a short time, cooled and ice water added to dissolve all the solid material. The oily layer is separated and combined with the subsequent ether extracts of the aqueous portion. The oil which remains after removal of the ether is distilled. There is thus obtained the desired product boiling at 114-116" C. at 1.4 mm.

The addition of an equivalent of hydrogen chloride gas to an ether solution of the base gives the monohydrochloride salt which melts at 232- 233 C. (dec.) The dihydrochloride salt has M. P. 275-276 C. (d'ec.) after crystallization from absolute alcohol;

we I EXAMPLE XX f Nj-( -pmdyo-N'-methuz ipeman Y A mixture of 6.5g. (0.04 mole) or N-(a-pyridyll-r-piperazine fhxampie XIX, 9.2 g. (0.20 mole) of iormicacid and 8.6 g; (0.10 mole) of formaldehyde is refluxed five hours. Excess hr 'drochloric acid' is added to' make the mixture acidic and the resulting solution is concentrated under reduced pressure. The residue is made basic with strong alkali and the basic product extracted with ether. The ether extracts are combined, dried, concentrated and distilled. There is thus obtained N-(a-pyridy1)-N'-methy1- piperazine, B. P. 106-107 C. at 2.7 mm. The dihydrochloride salt melts at 258-259 C. after crystallization from alcohol.

Compounds according to the invention have also been prepared in which R1 is an alkyl group containing up to four carbon atoms inclusive, such as propyl, isopropyl' and butyl. Examples for these compounds are: N-Q-phenanthr'ylmethyl-N-isopropylpiperazine and N-SJ-phenanthrylmethyl-N- (n-butyl) -piperazine. R1 may also be an alkanol' group containing up to four carbon atoms inclusive. Illustrative of these compounds are: N- (a-naphthylmethyl) -N- hydroxy-n propyll-piperazine and N -(fl-naphthylmethyl) -N t-hydroxy-n-butyl) piperazine. R3 and R4 may be a lower alkyl group containing up to four carbon atoms. Illustrative of such compounds are: N-(Q-phenanthrylmethyl) N -methyl-2,-n-propylpiperazine and ,N- (ll-phenanthrylmethyl) -N-methyl2,-n-butylpiperazine.

The following examples are illustrative o'f'the preparation of novel intermediates for the preparation of the final compounds according to the invention:

EXAMPLE XXI N- (9-fluorenyl) -N-carbethoxypiperaeine OHa-GH:

A mixture of 15.8 g. N-carbethoxypiperazine,

27 g. of Q-bromofluorine, and 5.8 g. of'sodiu'm 1 lization 'from ethyl acetate. The monohy'd'rochloride of this material melts at are-220 c.

with decomposition. The compoundis an intermediate for the preparation of the compound of Example IX.

' EXAMPLE XIHI N,N-dicarbethomy-2,5-dimethylpiperazine COOCzHs CE-CHa (3H2 N This compound is obtained as a by-product in the preparation of l-carbethoxy-2,5edimethylpiperazine. The preparation and constantsio'i this compound are disclosed in Example XXXV.

EXAMPLE XXIII n-PropyZ-p-chlorobenzyl chloride lO By reacting 49 g. of a-n-propyi-pchlorobenzy1 alcoholwith gaseous hydrogen chloride there is obtained the above mentioned compound which boils at 101-l03 C. at 1 mm. pressure.

EXAMPLE XXIV a-n-PropyZ-p-chlorobenzyl carbznol About 56.2 g. of p-chlorobenzaldehyde is reacted with the Grignard Reagent prepared from 98.4 g. of n-propyl bromide and 19.2 g. of magnesium metal. After refluxing the mixture for two hours a solution of ammonium chloride is added to destroy the Grignard complex. The resulting carbinol is isolated by distillation, it boils at 113-114 C. at 1.4mm. pressure. This compound is an intermediate for the preparation of the compound of Example XXIII.

EXAMPLE XXV 2- B-amz'noethylamino) -cyclohe:canol /CE2 /OH CH: (3-H C a NHCHzCHzNH:

To' a stirred solution of 1200 g.' of 69.4% ethylenediamine in 1000 cc. of methanol, main tained at 45-55 C., is added dropwise overa period of four hours a solution of 200 g. of cyclohexene oxide in cc. of methanol. Fractional distillation of the mixture yields the product, having the formula above, as a colorless oil which boils at 122-123 C. at 1.2 mm. The liquid sets to a greasy solid which melts, at 47-51" C. after one recrystallization from ligroin. This amine forms a dihydrochloride in ether, which is recrystallized from absolute ethanol as white needies melting at 229-230 C. (dec. 'This compound is an intermediate for the preparation of the compound of Example XXVI. r i

EXAMPLE Decahydroduinoxaiine A mixture of 38 g. of Z-(B-amindthylamino) cyclohexanol, 7.5 g. of Haney nickel, [and 200 pounds (cold) hydrogen is heated at 200 C. in a steel bomb with shaking for 6 hours. The resulting mixture is recrystallized once from dry ether; and then from low-boiling ligroin to constant melting point at -15l C. The product is in the form of white needles. A solution of the amine in ethanol when treated with etheareal hydrogen chloride gives the dihydrochloride, which recrystallizes from methanol as a white granular solid, melting-point 365 C. This compound is an intermediate for the preparation of compound of Example XXVII,

'11 EXAMPLE xxvn N-carbethoxydecahydroquinoaraline I I CH2 CH2 CH2 N (30002115 In the manner described in Example XXV, 15.4 g. of decahydroquinoxaline and 12 g. of ethyl chlorocarbonate react to form the compound represented by the'abov'e formula. The product is a colorless oil which boils at 107-109 C. at 0.6 mm. This compound is an intermediate for the preparation of the compound of Example XXV III.

EXAMPLE XXVIII N carb ethoxy-N -methyldecahydroquinoralin e CH2 N EXAMPLE XXIX N-methyldecahydroquinomaline CH2 N Hydrolysis of 17.5 g. of N-carbethoxy-N- methyldecahydroquinoxaline with 36 cc. of 12 N hydrochloric acid in the usual manner yields the compound of the above structure. The product is a colorless oil which boils at 88-90 C. at 8 mm. This compound is an intermediate for the preparation of the final compound of Example XVI.

EXAMPLE XXX 1,2-dimethyl-4-carbethorypiperazine or 1,3-dimethyZ-4-ccroethomypipemzine on: (13113 a. CHO H: on, CH:

' 01 CH: H: C H2 C H C Ha N 6 (10002115 OOCEHI,

In the manner described in Example XX, 45 g. of the compound which is either 2-methyl-4- carbethoxypiperazine or Z-methyl-l-carbethoxypiperazine is combined with 3 0 g. of anhydrous formic acid and 23 g. of formalin. The product, which is represented by one of the above formulae, is a colorless oil which boils at 114 C. at '10 mm., n =1.4633. Since the exact structure of the intermediate was not determined, it is not possible to state which isomer is obtained in the example or in Examples X-XXI-XXXIV and XIII-XIV.

EXAMPLE XXXI 1,2-dimethylpipemzz'ne o r 1,3-dimethylpiperazirte N\ N\ om (IE-CH3 (Fm CH2 m on, cm CH-CH3 By the procedure of Example IX, 32.3 g. of the compound described in Example XXX and '78 cc. of 12 N hydrochloric acid react to give the product having one of the formulae above. The compound is a colorless oil which boils at 128- C. This compound is a useful intermediate for the preparation'of the compound of Example XIII.

EXAIWPLE XXXII l-carbethoxy-3,5-dimethyipipemeine or l-carbcth0my-2,6-dimethylpiperazme Following the procedure of Example XXXV, 40 g. of 2,6-dimethylpiperazine and 40 g. of ethyl chlorocarbonate are combined in an aqueous solution with the pH maintained at 3.5 to 4.0 by sodium acetate bufier, the compound represented by one of the above formulae, is obtained as a pale yellow oil which boils at 86-87" C. at 1.3 mm. This compound is an intermediate for the preparation of the compound of Example XXXIII.

EXAMPLE XXXIII 1-carbethoxy-3,4,5-trimethylpiperazine or I-carbethoxy-ZA-6trimethylpiperazine CH3 CH: 1!: i l CH5-CH CH-CH3 CH: CH:

(5H2 CH2 or CHa( /H CHCH:

When 51.5 g. of the 1-carbethoxy-3,5-(or 2,6-) dimethylpiperazine described in the preceding example is methylated according to the process of Example XX with 32 g. of anhydrous formic acid and 23 g. of formalin, the compound represented by the appropriate one of the above formulae is obtained as a colorless oil which boils at 136 C. at 22 mm. This compound is an intermediate for the preparation of the compound of Example XXXIV.

EXAMPLE XXXIV 1,2,6 trimethylpiperazine or 1,3,5 trimethyl- Hydrolysis of 36 g. of the compound described in the above example with 80 cc. of 12 N hydro? chloric acid gives the product having the app priate one of the above formulae. The p oduc is a pale yellow oil which boils at 144 C. at 7 mm. This compound is a valuable intermediate for the preparation of the final product of Example XIV.

EXAMPLE xxxv 1 -carbethomy-2,5-dimethylpiperazine The pH of a solution of 24 g. of 2,5-dimethylpiperazine in 20 cc. of water is adjusted to 3.5, using bromphenol blue as an indicator, with 6 N hydrochloric acid. To the stirred solution is added 23 g. of ethyl chlorocarbonate dropwise over a period of minutes. The pH of the reaction mixture is kept at 3.5 to 4.0 by the con current addition of saturated sodium acetate solution. When there is no longer any evidence of acid being liberated by the reaction, solid sodium hydroxide is added until the mixture is alkaline, and the oily product is collected with the aid of ether. The ethereal solution is dried over anhydrous sodium carbonate, and the product purified by distillation. The product represented by the formula above, is collected as a pale yellow oil which boils at 95 C. at 1.5 mm. A small amount of N,N'-dicarbethoxy-2,5-dimethylpiperazine, a white solid melting at 78 C., is collected as a by-product of the reaction. The compound 1-carbethoxy-2,5-dimethylpiperazine is an intermediate for the preparationof the compound of Example XXXVI.

EXAMPLE XXXVI 1-carbetho:ry-2,4,5-trimethylpipemeine EXAMPLE XXXVII 1,2,5-trimethylpiperazine C CH-CH;

UR H H! Hydrolysis of 12.7 g. of 1-carbethoxy-2,4,5- trimethylpiperazine by 28 cc. of 12 N hydrochloric acid gives the compound represented b the above formula. The product is a colorless oil which boils at 148 C. at 750 mm. This compound is a valuable intermediate for the preparation of the compound of Example XV.

It is noted that for some of the compounds having methyl substitution on the piperazine ring, the two alternatives are given as to the possible structure. This is necessitated by the fact that in starting with the dimethyl-substituted piperazine, it is difiicult to determine to which nitrogen the substituents will add. However, in any event, one or both of the possible resulting compounds are produced.

The N,N-disubstituted piperazines according to the invention are usually more soluble in water as salts and are therefore administered in the form of water-soluble salts when a rapid effeet is desired. Any acid which produces a water soluble salt and does not appreciably enhance the toxicity is suitable for use. Such acids as sulphuric, phosphoric, hydrochloric, hydrobromic, levulinie, acetic and tartaric are among those which are satisfactory. v Where a retarded effect is desired in obtaining the therapeutic results, salts of other non-toxic acids, such as tannic acid, which are very sparingly soluble in water, may be used. By using the latter salts the desired pharmacological. efi'ect will be slow in onset and relatively long in duration. The water soluble salts of these compounds of the invention may be satisfactorily administered in the form of water solutions. The bases and water insoluble salts, such as the tannic acid salt, as well as the water soluble salts, may be administered in the form of tablets and capsules. The following examples will 11-- lustrate these preparations.

EXAMPLE XXXVIII N ('9-Fluorenyl) -N' -methylpiperazine hydrochloride g 2 Distilled water, q. s cc This formula produces an aqueous solution containing 20 mg. of medicament per cc. The compounds of the invention may be dispensed in aqueous solution in suitable concentrations according to this example.

EXAMIPLEXXICLX The salts of the therapeutic compounds according to the present invention may also be dispersed in the usual tablet and capsule bases and dispensed in tablet or capsule form. Convenient concentrations are 10, 25, 50 or 1.00 mg. per tablet or capsule.

Others may readily adapt the invention for use under various conditions of service, by employing one or more of the novel features disclosed, or equivalents thereof. As at present advised with respect to the apparent scope of our invention, we desire to claim the following subject matter.

We claim:

1. A compound selected from the group consisting of bases of the following formula:

wherein R1 is a member selected from the class consisting of hydrogen. an alkyl group containeaesacac in'giup to 4 carbon atomsinclusive, an alkanol groupcontaining up to l carbon atoms inclusive; R2 is a member selected from the class consisting of diphenylethyl, naphthylmethyl, fiuorenyl, phenanthrylmethyl and diphenylallyl groups; R3 and R4 are members selected from the class consisting of hydrogen and lower alkyl groups containing up to 4 carbon atoms inclusive; and acid addition salts thereof.

2. The compound N-naphthylmethy1-N'-R1- piperazines wherein R1 is an alkyl group containing up to 4 carbon atoms inclusive.

3. The compound N-fiuoreny1-N'-R1-piperazines wherein R1 is an alkyl group containing up to 4 carbon atoms inclusive.

4. The compound N-(fi,s-diphenylethyl) -N'- R1 is an alkyl group containing up to four carbon atoms inclusive.

5. The compound N-(9-phenanthrylmethyD- Rl-piperazine wherein R1 is an alkyl group containing up to four carbon atoms inclusive.

6. The compound N-(v,'y-diphenylallyl) -N- R1 is an alkyl group containing up to'four carbon atoms inclusive.

7. The compound N-(c,e-diphenylethy1) -N'- methylpiperazine.

' 8. The compound N-(a-naphthyImethyD-N- methylpiperazine.

9. The compound N-(9-fluorenyl)-N'-methylpiperazine.

10. The compound N-(9-phenanthrylmethyD- N -methy1piperazine.

11. The compound N-(v,'y-diphenyla11y1) -N- methylpiperazine.

12. The process for preparing the compound N ('m diphenylaliyl) N methylpiperazine which comprises mixing N-methylpiperazine with a -dipheny1a1lyl halide in an inert solvent under anhydrous .conditions.

13. The process for preparing the compound is N (3,,3' diphenylethyl) N methylpipera'zine which comprises treating N-methylpiperazine with a pp-diphenylethyl halide.

14.. The process forpreparing the compound N (9 fluorenyl) N methylpiperazine which 1 comprises treating N-methylpiperazine with a 9-fiuorenyl halide.

15. The process for preparing the compound 116 N (9 phen'anthrylmethyl) -N"-'methylpiprazine which comprises treating N-methylpiper azine with a 9-phenanthrylmethy1 halide. 16. The process of preparing-a compound having the general formula:

CHz-- -C Hz, wherein R1 is a member selected from the class consisting of hydrogen, an alkyl group containing up to 4 carbon atoms, inclusive, an alkancl group containing up to l carbon atoms, inclusive; R2 is a member selected from the class consisting of dipnenylethyl, naphthylmethyl, fiuorenyl, phenanthrylmethyl, and diphenylallyl groups; and R3 and R4 are members selected from the class consisting of. halogen and lower alkylgroup containing up to 4 carbon atoms; inclusive; which comprises mixing an Rnpiperazine with an Rz-halide in an inert solvent under anhydrous conditions. v p

17. The-process for preparing the compound N (5, 3 diphenylethyl) N methylpiperazine which. comprises mixing an N-methylpiperazine with a fifi-diphenylethyl halide in an inert solvent under anhydrous conditions.

18. The process of preparing the compound N (9 fiuorenyl) N methylpiperazine which comprises mixing N-methylpiperazine with 9 halofluorene in an inert solvent under anhydrous conditions. i

19. They process for preparing the compound N (9 phenanthrylmethyl) N methylpiperazine which comprises mixing N-methylpiperr azine with 9-chloromethylphenanthrene in an inert solvent under anhydrous conditions.

20. The process for preparing the compound N (a. naphthylmethyl) N methylpiperazine which comprises mixing N-methylpiperazine with N-a-naphthylmethyl halide in an inert solvent under anhydrous conditions.

ARTHUR W. WESTON. KENNETH E. HAMLIN, JR.

No references cited. 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF BASES OF THE FOLLOWING FORMULA:
 16. THE PROCESS OF PREPARING A COMPOUND HAVING THE GENERAL FORMULA: 